As the technology develops, the semiconductor optoelectrical device has a great contribution in information transmission and energy conversion. For example, the semiconductor optoelectrical device can be applied to fiber-optic communication, optical storage and military system. Generally, the semiconductor optoelectrical device can be classified as three categories according to energy conversion type: converting electrical energy to light, such as light-emitting diode and laser diode; converting light to electrical energy, such as optical detector; converting the radiation energy of light to electrical energy, such as solar cell.
The growth substrate is very important to semiconductor optoelectrical devices. The semiconductor epitaxial layers of a semiconductor optoelectrical device are grown on the growth substrate, and the growth substrate also provides the supporting function to carry the semiconductor epitaxial layer. But, different semiconductor epitaxial layers need different growth substrates. In order to form the semiconductor epitaxial layer with high quality, it is important to choose a suitable growth substrate.
However, sometimes a good growth substrate is not a suitable carrier substrate for carrying the semiconductor epitaxial layer. Taking the light-emitting diode as an example, in the manufacturing processes of the red light diode, in order to form a better semiconductor epitaxial layer, GaAs substrate is generally selected as the growth substrate because the lattice constant of GaAs substrate is close to that of the semiconductor epitaxial layer though GaAs is opaque and has low heat dissipation, which is adverse to the ultra-bright light-emitting diode which requires good heat dissipation. Such kind of growth substrate with low heat dissipation ability would cause the light-emitting efficiency to decline dramatically.
In order to satisfy the different requirement of the growth substrate and the carrier substrate of semiconductor optoelectrical devices, the substrate transfer technology is developed. Namely, the semiconductor epitaxial layer is firstly formed on the growth substrate, and then the semiconductor epitaxial layer is bonded to the carrier substrate for further processing.
The known ultra-bright light-emitting diode is produced by wafer to wafer bonding. The bonding layer, which is composed of metal or non-metal material, is used to bond the semiconductor epitaxial layer and the heat-dissipation substrate together. However, the bonding layer of a single material would limit the flexibility of light-emitting diode design and the following wafer level package.